Gear and clutch arrangement for multi-speed transmission

ABSTRACT

A transmission is provided having an input member, an output member, three planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes a sun gear member, a planet carrier member, and a ring gear member. The torque transmitting devices include five clutches and one brake arranged within a transmission housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/984,557, filed on Nov. 1, 2007, which is hereby incorporated in itsentirety herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission havingeight or more speeds, three planetary gear sets and a plurality oftorque transmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

Automatic power transmissions are currently in widespread use inpassenger vehicles and trucks. As is well known, the automatictransmission provides a plurality of speed ratios in the forwarddirection and at least one speed ratio in the reverse direction. Thespeed ratios are established through the use of a plurality of planetarygearsets. The engagement of the gearsets is controlled by a number offluid-operated torque transmitting mechanisms, for example clutches andbrakes.

It has become a standard to provide at least four forward speed ratiosin automatic transmissions for use in passenger vehicles. More recently,automobile manufacturers have increased the forward speed ratios to sixand in some instances seven or eight. This, of course, requires theaddition of planetary gearsets. However, it is desirable to minimize thenumber of torque transmitting mechanisms to reduce cost and overall sizeof the transmission.

A number of the currently proposed eight speed planetary transmissionsprovide three planetary gearsets and six torque-transmitting mechanisms.One problem facing transmission designers and manufacturers is thepackaging of the planetary gearsets and the torque-transmittingmechanisms. It is preferable to arrange the gearsets andtorque-transmitting mechanisms in a way that minimizes the overall sizeof the transmission as well as reduces manufacturing complexity.

Therefore, there is a need for a new and improved multi-speedtransmission. The arrangement of the gearsets and thetorque-transmitting mechanisms of the transmission should minimize thesize and manufacturing complexity of the transmission.

SUMMARY

In an aspect of the present invention, a multi-speed transmission isprovided. The transmission has an input member, an output member, atransmission housing, a first, second, and third planetary gear set,five clutches and one brake.

The transmission housing has a first wall, a second wall, and a thirdwall extending between the first and second walls. The third planetarygear set is adjacent the first wall. The second planetary gear set isadjacent second wall. The first planetary gear set is between the secondand third planetary gear sets. Each planetary gear set has a sun gearmember, a ring gear member and a planet carrier member supporting aplurality of planet gears each configured to intermesh with at least oneof the sun gear member and the ring gear member.

The output member is continuously interconnected with the ring gearmember of the third planetary gear set. The input member is continuouslyinterconnected with the sun gear member of the second planetary gearset.

The sun gear member of the first planetary gear set is permanentlycoupled to the transmission housing. The planet carrier member of thesecond planetary gear set is permanently coupled to the planet carriermember of the third planetary gear set.

The transmission housing has a first area defined radially inward froman outer periphery of the planetary gear sets and axially bounded by thefirst wall and the third planetary gear set, a second area definedradially inward from the outer periphery of the planetary gear sets andaxially bounded by the first and third planetary gear sets, a third areadefined radially inward from the outer periphery of the planetary gearsets and axially bounded by the first and second planetary gear sets, afourth area defined radially inward from the outer periphery of theplanetary gear sets and axially bounded by the second planetary gear setand the second wall, and a fifth area defined radially inward from thethird wall and radially outward from the outer periphery of theplanetary gear sets and axially bounded by the first wall and the secondwall.

The first of the five clutches is selectively engageable to interconnectthe input member with the planet carrier member of the first planetarygear set. The second of the five clutches is selectively engageable tointerconnect the input member with the ring gear member of the secondplanetary gear set. The third of the five clutches is selectivelyengageable to interconnect the planet carrier member of the firstplanetary gear set with the sun gear member of the third planetary gearset. The fourth of the five clutches is selectively engageable tointerconnect the ring gear member of the first planetary gear set withthe sun gear member of the third planetary gear set. The fifth of thefive clutches is selectively engageable to interconnect the ring gearmember of the first planetary gear set with the ring gear member of thesecond planetary gear set. The brake is selectively engageable tointerconnect the planet carrier member of the third planetary gear setto the transmission housing.

The first of the five clutches is disposed in the third area. The secondclutch is disposed in at least one of the third and fourth areas. Thethird clutch is disposed in the second area. The fourth clutch isdisposed in second area. The fifth clutch is disposed in at least one ofthe third, fourth and fifth areas. The brake is disposed in at least oneof the first, fourth and fifth areas.

The clutches and the brake are selectively engageable to establish atleast eight forward speed ratios and at least one reverse speed ratiobetween the input member and the output member.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a diagram of a cross-section of a transmission according tothe principles of the present invention.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

Referring now to FIG. 1, an embodiment of a multi-speed transmission isgenerally indicated by reference number 10. The transmission 10 includesa transmission housing 11, an input shaft or member 12, and an outputshaft or member 14. The input member 12 is preferably connected to anengine (not shown) or to a turbine of a torque converter (not shown).The output member 14 is preferably connected with a final drive unit(not shown) or transfer case (not shown). In the example provided, theoutput member 14 is located on an axis different from a longitudinalaxis defined by the input member 12. Accordingly, the output member 14may exit on a same side of the transmission 10 as the input member 12,thereby providing, for example, a front wheel drive transmissionconfiguration.

The transmission 10 includes a first planetary gear set 16, a secondplanetary gear set 18, and a third planetary gear set 20. The planetarygear sets 16, 18, and 20 are connected between the input member 12 andthe output member 14. In a preferred embodiment of the presentinvention, the first planetary gear set 16 is a planetary gear set thatincludes a sun gear member 22, a ring gear member 24 and a carriermember 28 that rotatably supports a set of pinion gears 32, 34. Piniongears 32, 34 are configured to intermesh with each other, sun gearmember 22 and ring gear member 24. Moreover, sun gear member 22 isfixedly connected to the transmission housing 11 of the transmission 10for preventing rotation of sun gear member 22. Ring gear member 24 isconnected for common rotation with a first interconnecting shaft ormember 38 and a second interconnecting shaft or member 39. Carriermember 28 is connected for common rotation with a third interconnectingshaft or member 40 and a fourth interconnecting shaft or member 45.

The second planetary gear set 18 includes a sun gear member 42, a ringgear member 44 and a carrier member 46 that rotatably supports a set ofpinion gears 48. Pinion gears 48 are configured to intermesh with bothsun gear member 42 and ring gear member 44. Sun gear member 42 isconnected for common rotation with the input member 12 and a fifthinterconnecting shaft or member 43. Carrier member 46 is connected forcommon rotation with a sixth interconnecting shaft or member 47. Ringgear member 44 is connected for common rotation with a seventhinterconnecting shaft or member 50.

The third planetary gear set 20 includes a sun gear member 52, a ringgear member 54 and a carrier member 56 that rotatably supports a set ofpinion gears 58. Pinion gears 58 are configured to intermesh with bothsun gear member 52 and ring gear member 54. Sun gear member 52 isconnected for common rotation with an eighth interconnecting shaft ormember 60. Ring gear member 54 is connected for common rotation with theoutput member 14. Carrier member 56 is connected for common rotationwith the sixth interconnecting member 47.

The transmission 10 includes a variety of torque-transmitting mechanismsor devices including a first clutch 70, a second clutch 72, a thirdclutch 74, a fourth clutch 76, a fifth clutch 78, and a brake 80. Thefirst clutch 70 is selectively engagable to connect the fifthinterconnecting member 43 with the fourth interconnecting member 45. Thesecond clutch 72 is selectively engagable to connect the fifthinterconnecting member 43 with the seventh interconnecting member 50.The third clutch 74 is selectively engagable to connect the thirdinterconnecting member 40 with the eighth interconnecting member 60. Thefourth clutch 76 is selectively engagable to connect the secondinterconnecting member 39 to the eighth interconnecting member 60. Thefifth clutch 78 is selectively engagable to connect the firstinterconnecting member 38 to the seventh interconnecting member 50. Thebrake 80 is selectively engagable to connect carrier member 56 to thetransmission housing 11 to restrict rotation of carrier member 56.

The transmission 10 is capable of transmitting torque from the inputmember 12 to the output member 14 in preferably at least eight forwardtorque ratios and two reverse torque ratios. Each of the forward torqueratios and the reverse torque ratios are attained by engagement of oneor more of the torque-transmitting mechanisms (i.e. first clutch 70,second clutch 72, third clutch 74, fourth clutch 76, fifth clutch 78,and brake 80). Those skilled in the art will readily understand that adifferent speed ratio is associated with each torque ratio. Thus, eightforward speed ratios may be attained by the transmission 10.

The transmission housing 11 includes a first end wall 102, a second endwall 104, and a third wall 106. The third wall 106 interconnects betweenthe first and second end walls 102 and 104 to provide a space or cavity108 in which the planetary gear sets 16, 18, and 20 and thetorque-transmitting mechanisms 70, 72, 74, 76, 78, and 80 are located.Further, the cavity 108 has a plurality of areas or Zones A, B, C, D,and E in which the plurality of torque transmitting mechanisms 70, 72,74, 76, 78, and 80 are specifically positioned, in accordance with thepreferred embodiments of the present invention.

As shown in FIG. 1, Zone A is defined by the area or space bounded:axially on the left by the first end wall 102, on the right by planetarygear set 20, radially inward by a reference line “L” which is alongitudinal line that is axially aligned with the input shaft 12, andradially outward by a reference line “M” which is a longitudinal linethat extends adjacent an outer diameter or outer periphery of theplanetary gear sets 16, 18, and 20. While reference line “M” isillustrated as a straight line, it should be appreciated that referenceline “M” follows the outer periphery of the planetary gear sets 16, 18,and 20, and accordingly may be stepped or non-linear depending on thelocation of the outer periphery of each of the planetary gear sets 16,18, and 20. Zone B is defined by the area bounded: axially on the leftby planetary gear set 20, axially on the right by planetary gear set 16,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone C is defined by the area bounded: axially on the left byplanetary gear set 16, axially on the right by planetary gear set 18,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone D is defined by the area bounded: axially on the left byplanetary gear set 18, axially on the right by the second end wall 104,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone E is defined by the area bounded: axially on the left bythe first end wall 102, axially on the right by the second end wall 104,radially inward by reference line “M” and radially outward by the thirdwall 106.

The torque transmitting mechanisms 70, 72, 74, 76, 78, and 80 areintentionally located within specific Zones in order to provideadvantages in overall transmission size, packaging efficiency, andreduced manufacturing complexity. In the particular example shown inFIG. 1, the torque transmitting mechanism 80 is in Zone A, the torquetransmitting mechanisms 74 and 76 are in Zone B, and the torquetransmitting mechanisms 70, 72 and 78 are in Zone C.

However, the present invention contemplates other embodiments where thetorque transmitting mechanisms 70, 72, 74, 76, 78, and 80 are disposedin the other Zones. The feasible locations of the torque-transmittingdevices 70, 72, 74, 76, 78, and 80 relative to the Zones are illustratedin Chart 1. An “X” in the chart indicates that the present inventioncontemplates locating the particular torque transmitting device in thereferenced Zones. An “O” in the chart indicates that the presentinvention contemplates that it is not feasible to locate the particulartorque transmitting device in the referenced Zone.

CHART 1 TORQUE TRANSMITTING ZONE ZONE ZONE ZONE ZONE DEVICES A B C D E80 X ◯ ◯ X X 78 ◯ ◯ X X X 76 ◯ X ◯ ◯ ◯ 74 ◯ X ◯ ◯ ◯ 70 ◯ ◯ X ◯ ◯ 72 ◯ ◯X X ◯

For example, the present invention provides that brake 80 may be locatedin Zone A, D, or E, but may not be located in Zones B or C. It should beappreciated that each of the torque transmitting devices 70, 72, 74, 76,78, and 80 may be located in a permissible Zone, as indicated in Chart1, independently of the location of any of the other torque transmittingdevices 70, 72, 74, 76, 78, and 80.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; atransmission housing having a first wall, a second wall, and a thirdwall extending between the first and second walls; a first, second andthird planetary gear set disposed within the transmission housing,wherein the third planetary gear set is adjacent the first wall, thesecond planetary gear set is adjacent second wall, and the firstplanetary gear set is between the second and third planetary gear sets,each planetary gear set having a sun gear member, a ring gear member anda planet carrier member supporting a plurality of planet gears eachconfigured to intermesh with at least one of the sun gear member and thering gear member, wherein the output member is continuouslyinterconnected with the ring gear member of the third planetary gearset, wherein the input member is continuously interconnected with thesun gear member of the second planetary gear set, wherein the sun gearmember of the first planetary gear set is permanently coupled to thetransmission housing, wherein the planet carrier member of the secondplanetary gear set is permanently coupled to the planet carrier memberof the third planetary gear set, and; wherein the transmission housinghas a first area defined radially inward from an outer periphery of theplanetary gear sets and axially bounded by the first wall and the thirdplanetary gear set, a second area defined radially inward from the outerperiphery of the planetary gear sets and axially bounded by the firstand third planetary gear sets, a third area defined radially inward fromthe outer periphery of the planetary gear sets and axially bounded bythe first and second planetary gear sets, a fourth area defined radiallyinward from the outer periphery of the planetary gear sets and axiallybounded by the second planetary gear set and the second wall, and afifth area defined radially inward from the third wall and radiallyoutward from the outer periphery of the planetary gear sets and axiallybounded by the first wall and the second wall; a first clutchselectively engageable to interconnect the input member and the sun gearmember of the second planetary gear set with the planet carrier memberof the first planetary gear set; a second clutch selectively engageableto interconnect the input member and the sun gear member of the secondplanetary gear set with the ring gear member of the second planetarygear set; a third clutch selectively engageable to interconnect theplanet carrier member of the first planetary gear set with the sun gearmember of the third planetary gear set; a fourth clutch selectivelyengageable to interconnect the ring gear member of the first planetarygear set with the sun gear member of the third planetary gear set; afifth clutch selectively engageable to interconnect the ring gear memberof the first planetary gear set with the ring gear member of the secondplanetary gear set; a brake selectively engageable to interconnect theplanet carrier member of the third planetary gear set to thetransmission housing; wherein the first clutch is disposed in the thirdarea, the second clutch is disposed in at least one of the third andfourth areas, the third clutch is disposed in the second area, thefourth clutch is disposed in second area, the fifth clutch is disposedin at least one of the third, fourth and fifth areas, and the brake isdisposed in at least one of the first, fourth and fifth areas; andwherein the clutches and the brake are selectively engageable toestablish at least eight forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 2. Thetransmission of claim 1 wherein the first clutch is disposed in thethird area, the second clutch is disposed in the third area, the thirdclutch is disposed in the second area, the fourth clutch is disposed inthe second area, the fifth clutch is disposed in the third area, and thebrake is disposed in the first area.
 3. The transmission of claim 1wherein the second clutch is disposed within the third area.
 4. Thetransmission of claim 1 wherein the second clutch is disposed within thefourth area.
 5. The transmission of claim 1 wherein the fifth clutch isdisposed within the third area.
 6. The transmission of claim 1 whereinthe fifth clutch is disposed within the fourth area.
 7. The transmissionof claim 1 wherein the fifth clutch is disposed within the fifth area.8. The transmission of claim 1 wherein the brake is disposed within thefirst area.
 9. The transmission of claim 1 wherein the brake is disposedwithin the fourth area.
 10. The transmission of claim 1 wherein thebrake is disposed within the fifth area.
 11. The transmission of claim 1wherein the first planetary gear set has a first plurality of pinionsand a second plurality of pinions rotatably supported by the planetcarrier member wherein the first plurality of pinions intermeshes withthe sun gear member and the second plurality of pinions intermeshes withthe ring gear member.